Origins of Invasive French

BroomAnnabelle Kleist

PhD Candidate, UC-Davis

Spatio-Temporal Stages of the Invasion

Process

Transport Colonization EstablishmentLandscape

Spread

Species whose propagules are

transported over long distances may become “casual” in

a new region

Abiotic factors determine whether propagules survive in the new habitat and affect growth

rates

Several processes create “biotic resistance” to

establishment, suppressing non-

native species’ reproductive rates

Spread rates depend on

establishment, dispersal ability,

habitat connectivity, etc

Hybridization and Invasion

Zebra + Donkey = Zeedonk (sterile)

Tamarix chinensis + T. ramosissima = invasive Tamarix in the States (not sterile)

Hybridization and Invasion

T. chinensis + T. ramosissima = invasive Tamarix

Evolutionary relationships

among invasive broomsFrench broom characteristics

French Broom

French Broom Distribution

Horticulture Connection: Sweet

Broom

Putative close relative of French broom

• Evolutionary relationships unclear because it is sold under a variety of scientific names

Common scientific names:

• Cytisus spachianus, Teline stenopetala sspspachiana, G. spachiana, and T. canariensis

Sweet broom

Genistacanariensis

Genistastenopetala

Genistamonspessulana

1 2

3

4

French broom identity: Hypotheses

Rationale:

• Species identity of invasive French broom is unknown

• Species identity of ornamental sweet broom is unclear

• Contribution of currently available ornamental brooms to invasive populations is unknown

1. Identify sources of invasive broom

populations in CA

2. Determine whether hybridization between

ornamental cultivars and invasive

populations has occurred

Objectives:

Phylogenetic Approach

Experimental Design

Sampling:

>20 invasive populations throughout CA

Collect sweet broom from >10 nurseries and landscape plantings

Data Analysis:

Reconstruct relationships among organisms using Maximum parsimony and Bayesian analyses

Data Collection:

DNA extracted from each individual

Sequence 4 DNA regions from each plant

• 2 nuclear: ETS and ITS (+ 8 sequences per invasive or ornamental individual)

• 2 chloroplast: trnL-F and tRNA-leu

California Sampling

Populations Sampled

Total # of Invasive Populations: 23

Total # of Landscape Plantings: 7

Total # of Nursery Plants: 5

Invasive

population

Landscape planting

Nursery plant

Methods: Molecular Phylogenetics

Phylogenetic trees show evolutionary relationships

Hypotheses and Expected Results

Invasive French broom

Invasive French broom

Ornamental sweet broom

1.

Invasive French broom

Invasive French broom

Ornamental sweet broom

Ornamental sweet broom

2.

Ornamental sweet broom does contribute to invasive

broom populations

Ornamental sweet broom may not be contributing to invasive broom populations

Alternatively

Chloroplast Results

Invasive “French

Broom” Group

Sweet broom

• Invasive “French Broom”• Genista monspessulana• Genista canariensis

• All ornamental and landscape sweet broom

• Some invasive brooms from urban invasions

• G. canariensis• G. stenopetala

ITS Results(nuclear region)

Sweet broom Group

• Ornamental and landscape clones

• ½ of the sequences from 5 invasive broom individuals

• Genista stenapetala and Genista canariensis

Invasive “French

broom” Group

• Invasive “French broom” sequences

• Genista monspessulana

Conclusions

Ornamental Brooms:

• Ornamental sweet broom most likely contributes via hybridization to invasive broom populations

• At least 2 different things are sold as Sweet Broom:1. G. stenopetala2. G. stenopetala and G. canariensis hybrid

Invasive French broom:

Most of the invasive French broom in CA is G. monspessulana

sometimes

Next Steps

1. What are the cultivated sources and introduction history of

invasive French broom populations in natural and urban areas of

California?

Trace the origins and spread of invasive populations by characterizing genetic structure in the native and introduced range

2. Do French broom populations have similar patterns of genetic

diversity, introduction, and structure in California and

Australia?

Trace the origins and spread of invasive populations by characterizing genetic structure in the native and 2 introduced ranges

Acknowledgements

Jasieniuk Lab:

Miki Okada, Anna Sherwood, Lindsay Clark,

Helpful professors at UCD:

Marie Jasieniuk, Joe DiTomaso, Dan Potter, Kevin Rice

Funding:

UC Davis Department of Plant Sciences GSR, Jastro-Shields, Davis Botanical Society, California Weed

Science Society